Said containers used in the above domain are often constituted by pots of cylindro-conical or other shape, generally, but not exclusively, made of synthetic material of the PVC type.
These pots are filled at a high rate by a potting machine which dispenses to each of them a dose of earth or any other substrate. The rate of these machines is of the order of 1000 to 1200 pots per hour. Downstream of this potting machine of any known type, the pots receive the plants and are then directed towards storage areas where they remain during the period of culture and growth.
During this period, the plants must undergo different treatments, such as manual or chemical weeding, fertilizing, watering.
Chemical weeding operations and weeding by hand are expensive.
In order to avoid these operations, it is known that nursery-men and horticulturists place protective covers on the pots or containers, above the earth or substrate which surrounds the roots, and around the stem of the plant or shrub; one example of a cover is described in Patent FR 2 146 516 to Albert LEFEUVRE which specifies that such covers may be constituted by a sheet of deformable material, generally of plastics material which presents a central opening joined to the contour of the cover following the shape of the pot or container by a continuous slot in order to engage the stem therein when these covers are placed in position.
Said covers, on the one hand, prevent the weeds from developing and, on the other hand, oppose too rapid an evaporation of the watering water. Various materials may be used for producing these covers and, at the present time, there are preferably used, jointly or not with a frame, air- and water-permeable sheets of woven or non-woven, knitted or non-knitted textile type, or a microperforated film as described in Patent Application 2 633 803 of Jul. 7, 1988 (to the firm HOLZSTOFF) concerning a composite agro-textile and applications thereof.
The drawback of these cover positioning systems is that man-power is always required, whilst all the operations of filling earth in the containers, of making a hollow at the centre of the potted earth and of planting therein a calibrated or non-calibrated clod containing the roots and from which projects the stem of a plant or shrub, may and are for the major part, and at least for the first two, generally carried out with automatic machines at a high rate, as indicated hereinabove, viz. 1000 to 1200 pots per hour. In fact, no simple enough automatic system has made it possible up to the present time to take into account all the shapes and sizes of stems to place a cover above without risk of injuring them, all the more so as it is desired to follow the same rate as the potting machine located upstream.
The problem raised is therefore that of being able to position a cover on any container, filled with substrate or earth, and adapted to receive a plant, so that at least the operations necessary for potting and protecting the surface of the substrate may be carried out automatically at a high rate and any manual operation is eliminated, or at least the cost thereof reduced, particularly and likewise for the operation of planting; this must be able to be effected whatever the characteristics of said plant or plantation.
Another object of the invention is to ensure satisfactory growth of the plants with reduced watering, which leads to substantial savings but also avoids leaching of the substrate which is detrimental to the action of the fertilizers, the quantity of which may consequently be reduced.